In the News (Sun 18 Feb 18)

The number of planets dropped to the eight significantly larger bodies that had cleared their orbit (Mercury, Venus, Mars, Earth, Jupiter, Saturn, Uranus and Neptune), and a new class of dwarf planets was created, initially containing three objects (Ceres, Pluto and Eris).

Smaller terrestrial planets lose most of their atmospheres because of this accretion, but the lost gases can be replaced by outgassing from the mantle and from the subsequent impact of comets.

The existence of actual interstellarplanets is considered likely based on computer simulations of the origin and evolution of planetary systems, which often include the ejection of bodies of significant mass.

A planet is generally considered to be a relatively large mass of accreted matter in orbit around a star that is not a star itself.

All the currently accepted planets in the solar system are named after Roman gods, except for Uranus (named after a Greek god) and the Earth, which was not seen as a planet by the ancients but rather the centre of the universe.

No interstellarplanet is known to date, but their existence is considered a likely hypothesis based on computer simulations of the origin and evolution of planetary systems, which often include the ejection of bodies of significant mass.

The central bulge of the galaxy is blocked to observation in the visible wavelengths, due to the interference by interstellar dust.

Interstellar dust is formed through several different processes that take place during the lifetime of stars.

Scientists could tell it came from interstellar space because it was not affected by the presence of any planet, and because it flowed from precisely the same direction as neutral interstellar gas, which had been detected before.

A planet is generally considered to be a relatively large mass of accreted matter in orbit around a star.

The eight largest planets are universally recognised as such (although Jupiter, Saturn and Neptune are not strictly nonlumious since they emit more radiation than they receive from the Sun), and for this reason are often universally referred to as "major planets", but there is controversy over Pluto and other smaller objects.

Pheonix Planet - was one of the earlier names for the discovered pulsar planets, as in a possibility of rising from the ashes of the supernova's dust.

The eight largest planets (which are also the eight nearest to the Sun) are universally recognised as such, and for this reason are often universally referred to as "major planets", but there is controversy over Pluto and other smaller objects.

A planet is a body that directly orbits a star, is large enough to be round because of self gravity, and is not so large that it triggers nuclear fusion in its interior.

The mission objective of the Voyager Interstellar Mission (VIM) is to extend the NASA exploration of the solar system beyond the neighborhood of the outer planets to the outer limits of the Sun's sphere of influence, and possibly beyond.

Penetration of the heliopause boundary between the solar wind and the interstellar medium will allow measurements to be made of the interstellar fields, particles and waves unaffected by the solar wind.

The first feature to be encountered by a spacecraft as a result of this interstellar wind/solar wind interaction will be the termination shock where the solar wind slows from supersonic to subsonic speed and large changes in plasma flow direction and magnetic field orientation occur.

voyager.jpl.nasa.gov /mission/interstellar.html (893 words)

Exopolitics: A Decade of Contact - PART ONE - UFO Evidence(Site not responding. Last check: 2007-11-06)

Earth is a life-experiment planet, and most of the life forms of Earth have been seeded and carefully cultivated by Universe society scientists.

More advanced planets have a high level of civilization and standard of living, along with the knowledge that a material life is but a transitory stage of development for a more fundamental, non-temporal being known as the soul.

Five of six planets discovered in 1999 are in the "habitable zone." This means their environments can support liquid water, a prerequisite for life.

An interstellarplanet is a (so far hypothetical) type of rogue planet that has been ejected from its star system by a proto-gas giant to become an outcast, drifting in interstellar space.

It is calculated that for an Earth-sized planet at a kilobar hydrogen atmospheric pressures in which a convective gas adiabat has formed, geothermal energy from residual core radioisotope decay will be sufficient to heat the surface to temperatures above the melting point of water.

If interstellarplanets are considered as stars (brown sub-dwarfs) then the debris could coalesce into planets, meaning the disks are proplyds.

Called "interstellarplanets" because they would exist between the stars but no longer in orbit around an original parent star, they have never been directly observed or proved to even exist.

Over a period of several million years, one of two things happened to these planets: either they slammed into Jupiter and made it even bigger, or else they came so close to Jupiter that they were catapulted by gravity completely out of the solar system, never to return.

These interstellar wanderers could also have arisen as a natural outcome of the formation of stars, and not just during the formation of the system we live in.

These clouds are the birthplace of stars and planets; they're also the debris left behind when stars explode.

Planets such as Saturn, Uranus, Neptune and Pluto would be fully exposed to interstellar atoms and molecules.

science.nasa.gov /headlines/y2004/17dec_heliumstream.htm (963 words)

According to an interstellar medium...(Site not responding. Last check: 2007-11-06)

When she says "virtually," she's serious: The interstellar medium now has about 0.1 hydrogen atom per cubic centimeter (and that's 1,000 times as dense as the last cloud).

Since the position of the heliopause depends on the balance between the strength of the flow of interstellar medium and the strength of the solar wind, if the interstellar medium gets much denser, it could shrink the heliopause significantly.

If the heliopause shrinks to inside Earth's orbit, our planet would be exposed directly to the interstellar medium, possibly causing an increase in cosmic rays at the top of the atmosphere, a decrease in ultraviolet radiation, and other changes that could affect the atmosphere, weather and life in unpredictable ways.

whyfiles.org /017planet/gas_cloud2.html (574 words)

USATODAY.com - Voyager I on verge of interstellar space(Site not responding. Last check: 2007-11-06)

The Voyager 1 spacecraft, our planet's most distant probe, has reached the solar system's edge and may have entered the uncharted reaches of interstellar space, say scientists.

But scientists disagree on whether the probe has actually crossed into interstellar space, where the effects of the sun's solar wind no longer predominate, or if it is merely on the cusp of this transition.

Measuring the properties of interstellar space has long interested astronomers, who want to understand the unique properties of the vacuum between stars.

www.usatoday.com /tech/news/2003-11-05-voyager-edge_x.htm (556 words)

[No title](Site not responding. Last check: 2007-11-06)

Even without a sun-like star to heat them up, these exiled interstellar bodies could be wrapped in dense hydrogen atmospheres that would trap the warmth generated by the planets' natural radioactivity, David Stevenson wrote in the current edition of the journal Nature.

Bodies with about the same mass as Earth's were thought to follow two paths in those early times: either they would slam into a large planet like Jupiter and add to its mass, or come within range of a large planet's gravitational pull and be catapulted out into the void.

"You might not actually see a beautiful starry sky." In any event, Stevenson acknowledged that interstellarplanets are virtually impossible to detect from Earth with current technology, making the theory of their existence very hard to test.